During production of crankshafts it is necessary to grind the crankpin of the crankshaft to size on a grinding machine. In order to ensure that the grinding process terminates as soon as a desired dimension has been attained it is necessary to check the crankpin continuously using an in-process measuring method during the machining process, in particular with regard to its diameter and roundness. EP-A-0859689 discloses such a measuring device.
Known from EP-A-1370391 is a measuring device of this type that is used for in-process measuring of crankpins during a grinding process on a grinding machine. The known measuring device has a measuring head that is connected pivotably about a first pivot axis to a base body of the measuring device via a linkage. The known measuring device furthermore has means for pivoting the measuring head in and out of a measuring position respectively. For performing an in-process measurement on a crankpin, the measuring head is pivoted inwardly by the means provided for this purpose into a measuring position in which the measuring head is positioned, for instance by means of a measuring prism, against the crankshaft to be measured. During the grinding process, the crankpin performs an orbital rotation about the rotational axis of the crankshaft. The grinding wheel remains in contact with the crankpin and to this end is movably carried radially to the rotational axis of the crankshaft. The measuring head reproduces the movements of the crankpin in order to ensure that measurements can be performed on the crankpin during the entire grinding process. To this end the base body of the measuring device is connected to a base body of the grinding machine so that the measuring device is moved in the radial direction of the crankshaft synchronously with the grinding wheel of the grinding machine during the grinding process.